The Queen was today marking the 50th anniversary of her accession to the throne with a poignant visit to a cancer unit in memory of her father, King George VI.

The Queen was today marking the 50th anniversary of her accession to the throne with a poignant visit to a cancer unit in memory of her father, King George VI.

On a day tinged with sadness, the Queen normally stays out of the public eye at Sandringham, the royal estate in Norfolk where George VI died half a century ago on Wednesday, February 6, 1952.

But because this year is her Golden Jubilee, the Queen decided to emerge from the privacy of Sandringham on Accession Day and commemorate her father, who died after suffering lung cancer. She was opening the £1.2m Macmillan Centre at the Queen Elizabeth Hospital in nearby King's Lynn.

George VI, a heavy smoker, survived an operation to remove his left lung, but later succumbed to a blood clot which caused a coronary thrombosis.

"The King is dead. Long live the Queen."

With these words the nation, and the Commonwealth, mourned the death of George VI and heralded the coming of a new Elizabethan era.

But for Elizabeth herself, Accession Day, when she came to the throne, is also the day her father died. Fifty years ago, she was in Kenya when the news reached her. She returned to Britain immediately, at the start of a reign which was to become the fifth longest in 1,000 years of English history - and could yet break more records.

Meanwhile, a Golden Jubilee portfolio of photographs was unveiled today to mark the 50th anniversary of the Queen's accession.

Photographers who were invited to take pictures of the Queen and the Duke of Edinburgh included their son, the Duke of York, and Canadian rock star Bryan Adams. The range of pictures was taken during the last three months of last year.

The photographers used backgrounds of their own choice including, for the first time in official royal photography of the Queen and Prince Philip, the use of digital techniques.

Also for the first time, official photographs - taken by John Swannell - of the Queen, alone and with Prince Philip, are available on the Internet at www.royal.gov.uk for anyone to use non-commercially.

Also today, the names of thousands of unsung heroes due to take centre stage in the biggest public relay in the UK were being announced.

Some 2,500 people, from a 94-year-old newspaper seller to an 11-year-old lifeguard, will carry the Queen's Jubilee Baton round the country. In all, 5,000 everyday heroes, aspiring athletes, celebrities and local dignitaries will carry the high tech baton - the Commonwealth Games' answer to the Olympic Torch - across 5,000 miles through 500 towns over 50 days.